Cushioning tool holder



` Aug. 24, 1943.D

w. J. WEBER@ 2,327,685 CUSHIONING TOOL HOLDER Filed July 25, 1941 wwwl'//////////////////]" Patented Aug. 24, 1943 oUsHIoNING `roer. nomma YWilliam J. Weberg, Chicago, Ill.

Application July 2 5, 1941, Serial No. 403,953

s Claims. Y (o1. ,ae-103) rlhis invention relates to ,improvements inrotary holders for fiying cutting tools ofthe type wherein a tool or bitis secured eccentrically of the face ofthe holder so as to produce acircular cut in the work.

The principal object of the invention is to provide a spring cushioningconnection between parts of the tool holder body so as to permit limitedyielding or cushioning movement of the tool relative to its drivingspindle. A further object of the invention is `to provide a simple andfacile means for adjusting the eiective tension of the cushioningsprings, and also to provide means at will to limit or dispense with thecushioning effect when desired.

The invention may best be understood by refi erence to the accompanyingdrawing, inV which Figure 1 is a bottomview of a tool holder body of myinvention, butwith the laterally adjustble tool-holding block removedtherefrom to show the novel features of the cushioning device moreclearly. v

Figure 2 is a section taken on line 2--2 of Figure 1, and indicating toan exaggerated ldegree the amount of limited relative movement betweenthe upper and lower parts of the tool holder.

Figure 3 is a section taken on line 3-,3 of Figure l.

Figure l is a section taken on line 4-4 of Figure 2.

In the embodiment of my invention illustrated in the drawing, the toolholder body is indicated generally at I0, and includes a top plate ordriving member ll which has a cylindrical shank I2 for suitableconnection with the driving spindle of a lathe, boring machine or thelike, and a separable bottom plate or tool support I3 which has means asusual for mounting a tool-holding block (not shown) for adjustmenttransversely thereof at varying distances from the axis of rotation ofthe tool body. In the form shown herein, the bottom plate has a pair ofribs I4, I4 formed across its bottom face, having undercut innervfacesI5, I5 to form a slot for receiving the tool holder block for adjustmenttoward and away from a closed end Wall I6. The tool holding block andits lateral adjusting means are not shown herein because they form nopart of the present invention.

The top plate Il has an annular recess I1 in its bottom face forreceiving an annular upstanding portion I8 of the bottom plate I3,preferably with a close, or lapping fit. The outer peripheries of thetop plate II and the flanged base I9 of said bottom plate are ush witheach other.

The shank I2 of the top plate also has a bore 20 therethrough which.receives a centrally disposed hub portion 2| of the bottom plate. Theouter end of the bore 20 is threaded to receive a screw 22 adjustablefrom the upper end of the shank I2, as shown in Figure 2. The purpose ofscrew 22 will presently be described.

VA plurality ,of bored recesses 25 and 26 are formed'adjacent theperiphery of the upstanding `portion I3 of the bottom plate, whichholes.open upwardly towardv the top Splate II and on axes parallel with theturning axis of` the tool holder body. In the form shown, four recesses25 and an equal number of recesses 26 are shown,

. '1 disposed alternately on the same diameters, but

it will be understood that the number and relationship of these recessesmay be varied, if desired. As vshown in-Figure 3, the Arecesses 25 eachhave concentric bolts 2l extending through the ribs UIll and the bottomflange I8 and passing upwardly through` the top plate II. Said boltshave lock nuts 28, 23 threaded on their upper ends. of the recesses 25,surrounding its respective bolt 2l, and maintained under compression totend to urge the top and bottom plates away from each other. The amountof yielding separation between said plates is limited and determined byadjustment of the b olts 2l and their lock nuts 28.

The recesses 25 each have other coil springs 3G therein, together withadjusting means for varying the total yielding compression of thesprings effective between the top and bottom plates.

Saidcompression adjusting means herein include bolts 32, 32 each havingan elongated head 33, a

fiange 34, and a shank 35 having threaded engagement with a collar 36.The head 33 of each bolt extends through a bore 3l in the top plate, andthe Iiange 34 abuts a shoulder 38 counterbored from the under face ofthe top plate II. The collar 36 is slidably mounted in the upper end ofits recess 26 but is restrained from rotation therein by pins 38, 38inset along opposite sides of said recess, as shown in Figure 4. A

Ycompression spring 30 is disposed in the bottom of each recess 26,in'abutting engagement with the collar 36, so that the amount ofcompression thereof can be increased or decreased by rotation of thebolt 32 associated therewith.

I have found that with a limited cushioning or yielding movementprovided by an arrangement such as above described, the cuttingeffectiveness of the tool carried by the holder is greatly improved inmany ways. The tool cuts with much greater smoothness and less heatingand A coil spring 29 is also mounted in each4 tool wear than heretofore.The work can also be cut to greater accuracy, with fewer changes inadjustment of the tool itself, since the com pression of the springs maybe sufficient to automatically feed the tool to the final dimensions, 5thus avoiding excessive stresses on the tool while it is cutting to suchfinal dimensions.

In practice, I find that the amount of yielding movement desired isrelatively small, usually being in theorder of,.say,` 5/ooo ofsanl-inchor less 10 for most purposes.. Moreoven, the desired amount of movementfor best results may vary considerably for various kinds of metal, forVary: ing hardnesses thereof, and for different cutting operations. Suchvariations, however,-can-readi 15 ily be ascertained by the operatorfromvexperb. ence and by experiment.

As a further feature of mydevicat willlbe-` observed that the yieldingor cushioning :move ment of the tool holder can be positively limited,20 or eliminated i entirely; by adjustment off the screw 2 2 A-wlfiiohfmay tbefdi'rectlyengagedK with; the end cf the-hub l` ofthe-bottom plate-l 3 ias Vsliovrnr in yfligure2.

Although I have lshownfandldesoribed on'e 4par--Yv 25 ticulan embodimentofmy inventionr it-v willlbe f understood that? I `/donot-lwislf1-to belimitedito theexactconstruction;showneanddescribedg but that I'various-changes fand modioationslmay be made* without departing from thespiritJ and 30 V scope ofA my invention as deiinedin theappendedclaims;A

I'claim as -my invention=r f 1.I Infa rotary-toolholdenva-rotaiybasemember," atool#supporting-memberadapted to holdj 35 a tool for ,feedinginrar direction Vextending ax# ially of said -tool liolder,-and-yieldingconnecting` means therebetween permitting limitedcrelati'veaxialrmovement 'of saidrmembers; said-' yielding connecting -means-being'-maintained-'under "suiiil' 40 cien-tj* compression 'to feed iatool torthe work throughthe distance of" relative Lmovement ,ofsaidin'iembers'.`

2;` In` a rotary -tool`- holder, Ia, rotary `base -meme ber-yatoolsupportin'g*member'adaptedto"hold^ 5 a'tool for feeding intadirecti'ion'extendingjaxiallyA of said-*too1 '-holder; andyielding"'compressionH meansV vtherebetween perrnitt'ingj relativeraxial movement of said'members in" the order of 'apl proximately'yiopoor less'..

3;"In a'rot'ary'tooll holder," a-rotarybasernem` ber, a `Vtoolsupporting ,member Vadajptedto"holda tool' for feeding 'in aA4directiorrextending ax: ially of said" tool holderf yielding connecting'means therebetween" permitting limited' ,relative aiial movement-ofsaid'members," and means `for adjusting the compression" of i said"connecting means Without increasing'` the amountof'relative axialmovement between said, members.

4. In a rotary tool holder, a rotary base member, a tool supportingmember adapted to hold a tool for feeding in a direction extendingaxially of said tool holder, a plurality of springs interposed betweensaid members and arranged in concentric relation about the axis ofrotation of said tool holder, and a plurality of connecting devicesmaintaining said springs under compression and limiting the relativeaxial movement betweenisaidmembers. v

5. Ina rotaryztool holdenarotaryf; base member, a tool supportingmember, a plurality of springs interposed between said members, aplurality of connecting devices maintaining said ysprings-undercompression and limiting the rela- 6r .Inf a rotary Ltoolh'olden;avrotaryibase.1mem bei', an toolz.: supporting .xmemberp aa plurality:`of;r springs,y Iinterposedrbetweenl said memberspar .plu-f. rality ofconnecting devices maintaining rsaidu springs :undenLcompressi-on;andlimitingrthe :relativen 'movement between'fi saidf members-,z andi afsingleaxially disposed. lscrewll carried :by onef'of"said"members-anwadjustablelfory direct-'engagee mentwith the. otherof=z'said;memberstoi provide additional" limitation of. 'relativemovement` there r between for. entirely eliminate suchrelativemove+ mentat williv '1;1 Inra Arotary tool/holder; a rotary l:base mem'.- ber anda tool supporting member:telescopicallyl mounted fer4 axial4 movement.relative'w-to reach other,i4 a# pluralityof "coilfsprings mountedebeetween `saidlmemb'ers, aUpluralityi of l bolts.:4 connectingsa-idimembersfor limited axial. movement with'fsaidg'springs maintainedrundercompression;v andfmeans-foradiusting the compressionof sai-di springsindependently of said connecting bolts:l

b'er -and a1tool supporting 1'member telescopicallyi. mountedforl axialImovement;Jr relative to cache other;A a# pluralityv of Y coilflspringsmounted- Lbee: f

tween -said"members,` a pluralityl ofboltsbconnecting said members forlimited axial movement withsaid springs imaintained under compression,

and means for adjusting the compression of satd springs independently ofsaiddconnectinglbolts,

including collars non-rotatably\ mountedilinJ-oner of said1Vmembe;fs-and abuttingr the adjacent rends...y v of- 'their nrespectivespringsfand1a-bolt threaded'. in each-fof said collars-#and lhavinga alhead Tproi;

jectingthrough'theother offsaid-membersg

